Last month, a plane and was forced to shut down one of its engines. Passengers reportedly heard a bang, and then the air conditioning shut off, which was probably a scary situation for everyone involved. But the plane still made it to its destination safely because, while engine problems after takeoff are rare, planes are designed to fly with only one engine.

for CNN, explained that not only is it safe for a plane to fly on one engine, but it’s also a situation that pilots spend a significant amount of time training for in simulators. And Drury would know. He completed a Ph.D. in Aviation Human Factors and Safety Management Systems and has been in aviation for about 40 years. He has also reportedly lost an engine while in the air before, so these aren’t theoretical claims from someone who has never flown a plane before.

Drury also pointed out that Australian law requires that any plane taking off has to be able to make it to its destination on a single engine. So at least in Australia, where the Qantas flight originated, as long as the plane has enough fuel, it can get to where it’s going safely. If it runs out of fuel, though, that would still obviously be a problem.

Part of why it’s so unusual for a plane to develop engine problems after take-off is that technicians are required to be meticulous about engine maintenance and have redundant safety procedures built in. So you don’t just have a single person inspecting the engines and doing the maintenance. You also have someone who comes behind them and checks to make sure everything was done correctly, and the engine is operating at 100 percent.

As the Qantas incident shows, all the ground tests, flight tests, and certification processes that are required still can’t guarantee an engine will never fail. And if you’re ever on a plane where an engine does go out, at least you know that it’s not the disastrous event it may feel like at the moment.